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| Author | Gkanatsiou, A.; Lioutas, C.B.; Frangis, N.; Polychroniadis, E.K.; Prystawko, P.; Leszczynski, M.; Altantzis, T.; Van Tendeloo, G. | ||||
| Title | Influence of 4H-SiC substrate miscut on the epitaxy and microstructure of AlGaN/GaN heterostructures | Type | A1 Journal article | ||
| Year | 2019 | Publication | Materials science in semiconductor processing | Abbreviated Journal | Mat Sci Semicon Proc |
| Volume | 91 | Issue | Pages | 159-166 | |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | AlGaN/GaN heterostructures were grown on “on-axis” and 2° off (0001) 4H-SiC substrates by metalorganic vapor phase epitaxy (MOVPE). Structural characterization was performed by transmission electron microscopy. The dislocation density, being greater in the on-axis case, is gradually reduced in the GaN layer and is forming dislocation loops in the lower region. Steps aligned along [11̅00] in the off-axis case give rise to simultaneous defect formation. In the on-axis case, an almost zero density of steps is observed, with the main origin of defects probably being the orientation mismatch at the grain boundaries between the small not fully coalesced AlN grains. V-shaped formations are observed in the AlN nucleation layer, but are more frequent in the off-axis case, probably enhanced by the presence of steps. These V-shaped formations are completely overgrown by the GaN layer, during the subsequent deposition, presenting AlGaN areas in the walls of the defect, indicating an interdiffusion between the layers. Finally, at the AlGaN/GaN heterostructure surface in the on-axis case, V-shapes are observed, with the AlN spacer and AlGaN (21% Al) thickness on relaxed GaN exceeding the critical thickness for relaxation. On the other hand, no relaxation in the form of V-shape creation is observed in the off-axis case, probably due to the smaller AlGaN thickness (less than 21% Al). The AlN spacer layer, grown in between the heterostructure, presents a uniform thickness and clear interfaces. |
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| Language | Wos | 000454537700022 | Publication Date | 2018-11-26 | |
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| ISSN | 1369-8001 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 2.359 | Times cited | 1 | Open Access | Not_Open_Access |
| Notes | Funding: This work was supported by the IKY Fellowships of Excellence for Postgraduate Studies in Greece-SIEMENS Program; the Greek General Secretariat for Research and Technology, contract SAE 013/8–2009SE 01380012; and the JU ENIAC Project LAST POWER Large Area silicon carbide Substrates and heteroepitaxial GaN for POWER device applications [grant number 120218]. Also part of the research leading to these results has received funding from the European Union Seventh Framework Program under Grant Agreement 312483 – ESTEEM2 (Integrated Infrastructure Initiative–I3). T.A. acknowledges financial support from the Research Foundation Flanders (FWO, Belgium) through a post-doctoral grant. | Approved | Most recent IF: 2.359 | ||
| Call Number | EMAT @ emat @UA @ admin @ c:irua:156200 | Serial | 5149 | ||
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| Author | Serrano-Sevillano, J.; Reynaud, M.; Saracibar, A.; Altantzis, T.; Bals, S.; van Tendeloo, G.; Casas-Cabanas, M. | ||||
| Title | Enhanced electrochemical performance of Li-rich cathode materials through microstructural control | Type | A1 Journal article | ||
| Year | 2018 | Publication | Physical chemistry, chemical physics | Abbreviated Journal | Phys Chem Chem Phys |
| Volume | 20 | Issue | 20 | Pages | 23112-23122 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | The microstructural complexity of Li-rich cathode materials has so far hampered understanding the critical link between size, morphology and structural defects with both capacity and voltage fadings that this family of materials exhibits. Li2MnO3 is used here as a model material to extract reliable structure–property relationships that can be further exploited for the development of high-performing and long-lasting Li-rich oxides. A series of samples with microstructural variability have been prepared and thoroughly characterized using the FAULTS software, which allows quantification of planar defects and extraction of average crystallite sizes. Together with transmission electron microscopy (TEM) and density functional theory (DFT) results, the successful application of FAULTS analysis to Li2MnO3 has allowed rationalizing the synthesis conditions and identifying the individual impact of concurrent microstructural features on both voltage and capacity fadings, a necessary step for the development of high-capacity Li-ion cathode materials with enhanced cycle life. |
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| Language | Wos | 000445220500071 | Publication Date | 2018-08-24 | |
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| ISSN | 1463-9076 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 4.123 | Times cited | 36 | Open Access | OpenAccess |
| Notes | This work was supported by the Spanish Ministerio de la Economı´a y de la Competitividad through the project IONSTORE (MINECO ref. ENE2016-81020-R). The research leading to these results has received funding from the European Union Seventh Framework Programme under Grant Agreement 312483 – ESTEEM2 (Integrated Infrastructure Initiative-I3). JSS and AS are grateful for computing time provided by the Spanish i2Basque Centers. MR acknowledges the Spanish State for its financial support through her post-doctoral grant Juan de la Cierva – Formacio´n (MINECO ref. FJCI-2014-19990) and her international mobility grant Jose´ Castillejos (MECD ref. CAS15/00354). S. B. acknowledges funding from the European Research Council (ERC starting grant #335078 Colouratom) and T. A. a postdoctoral grant from the Research Foundation Flanders (FWO). (ROMEO:yellow; preprint:; postprint:restricted ; pdfversion:cannot); ecas_sara | Approved | Most recent IF: 4.123 | ||
| Call Number | EMAT @ emat @c:irua:154782UA @ admin @ c:irua:154782 | Serial | 5062 | ||
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| Author | Nerl, H.C.; Pokle, A.; Jones, L.; Müller‐Caspary, K.; Bos, K.H.W.; Downing, C.; McCarthy, E.K.; Gauquelin, N.; Ramasse, Q.M.; Lobato, I.; Daly, D.; Idrobo, J.C.; Van Aert, S.; Van Tendeloo, G.; Sanvito, S.; Coleman, J.N.; Cucinotta, C.S.; Nicolosi, V. | ||||
| Title | Self‐Assembly of Atomically Thin Chiral Copper Heterostructures Templated by Black Phosphorus | Type | A1 Journal article | ||
| Year | 2019 | Publication | Advanced functional materials | Abbreviated Journal | Adv Funct Mater |
| Volume | 29 | Issue | 37 | Pages | 1903120 |
| Keywords | A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) | ||||
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| Language | Wos | 000478478400001 | Publication Date | 2019-07-17 | |
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| ISSN | 1616-301X | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 12.124 | Times cited | 1 | Open Access | OpenAccess |
| Notes | European Research Council, 2DNanoCaps TC2D CoG 3D2DPrint CoG Picometrics grant agreement No. 770887; Engineering and Physical Sciences Research Council, EP/P033555/1 EP/R029431 ; Science Foundation Ireland, HPC1600932 ; | Approved | Most recent IF: 12.124 | ||
| Call Number | EMAT @ emat @c:irua:161901 | Serial | 5362 | ||
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| Author | Celentano, G.; Rizzo, F.; Augieri, A.; Mancini, A.; Pinto, V.; Rufoloni, A.; Vannozzi, A.; MacManus-Driscoll, J.L.; Feighan, J.; Kursumovic, A.; Meledin, A.; Mayer, J.; Van Tendeloo, G. | ||||
| Title | YBa2Cu3O7−xfilms with Ba2Y(Nb,Ta)O6nanoinclusions for high-field applications | Type | A1 Journal article | ||
| Year | 2020 | Publication | Superconductor Science & Technology | Abbreviated Journal | Supercond Sci Tech |
| Volume | 33 | Issue | 4 | Pages | 044010 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | The structural and transport properties of YBa2Cu3O7−x films grown by pulsed laser deposition with mixed 2.5 mol% Ba2YTaO6 (BYTO) and 2.5 mol% Ba2YNbO6 (BYNO) double-perovskite secondary phases are investigated in an extended film growth rate, R = 0.02–1.8 nm s−1. The effect of R on the film microstructure analyzed by TEM techniques shows an evolution from sparse and straight to denser, thinner and splayed continuous columns, with mixed BYNO + BYTO (BYNTO) composition, as R increases from 0.02 nm s−1 to 1.2 nm s−1. This microstructure results in very efficient flux pinning at 77 K, leading to a remarkable improvement in the critical current density (J c) behaviour, with the maximum pinning force density F p(Max) = 13.5 GN m−3 and the irreversibility field in excess of 11 T. In this range, the magnetic field values at which the F p is maximized varies from 1 T to 5 T, being related to the BYNTO columnar density. The film deposited when R = 0.3 nm s−1 exhibits the best performances over the whole temperature and magnetic field ranges, achieving F p(Max) = 900 GN m−3 at 10 K and 12 T. At higher rates, R > 1.2 nm s−1, BYNTO columns show a meandering nature and are prone to form short nanorods. In addition, in the YBCO film matrix a more disordered structure with a high density of short stacking faults is observed. From the analysis of the F p(H, T) curves it emerges that in films deposited at the high R limit, the vortex pinning is no longer dominated by BYNTO columnar defects, but by a new mechanism showing the typical temperature scaling law. Even though this microstructure produces a limited improvement at 77 K, it exhibits a strong J c improvement at lower temperature with F p = 700 GN m−3 at 10 K, 12 T and 900 GN m−3 at 4.2 K, 18 T. | ||||
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| Language | Wos | 000525650500001 | Publication Date | 2020-04-01 | |
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| ISSN | 0953-2048 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.6 | Times cited | Open Access | OpenAccess | |
| Notes | This work was partially financially supported by EUROTAPES, a collaborative project funded by the European Commission’s Seventh Framework Program (FP7/2007–2013) under Grant Agreement No. 280432. This work has been partially carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom programme 2014-2018 and 2019-2020 under grant agreement N° 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 823717 – ESTEEM3 (Nano-engineered YBCO Superconducting Tapes for High Field Applications, NESTApp). G. C. acknowledges the support of Michele De Angelis for XRD measurements and calculations. | Approved | Most recent IF: 3.6; 2020 IF: 2.878 | ||
| Call Number | UA @ lucian @c:irua:168582 | Serial | 6394 | ||
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| Author | Abakumov, A.M.; Li, C.; Boev, A.; Aksyonov, D.A.; Savina, A.A.; Abakumova, T.A.; Van Tendeloo, G.; Bals, S. | ||||
| Title | Grain boundaries as a diffusion-limiting factor in lithium-rich NMC cathodes for high-energy lithium-ion batteries | Type | A1 Journal article | ||
| Year | 2021 | Publication | ACS applied energy materials | Abbreviated Journal | |
| Volume | 4 | Issue | 7 | Pages | 6777-6786 |
| Keywords | A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) | ||||
| Abstract | High-energy lithium-rich layered transition metal oxides are capable of delivering record electrochemical capacity and energy density as positive electrodes for Li-ion batteries. Their electrochemical behavior is extremely complex due to sophisticated interplay between crystal structure, electronic structure, and defect structure. Here we unravel an extra level of this complexity by revealing that the most typical representative Li1.2Ni0.13Mn0.54Co0.13O2 material, prepared by a conventional coprecipitation technique with Na2CO3 as a precipitating agent, contains abundant coherent (001) grain boundaries with a Na-enriched P2-structured block due to segregation of the residual sodium traces. The trigonal prismatic oxygen coordination of Na triggers multiple nanoscale twinning, giving rise to incoherent (104) boundaries. The cationic layers at the (001) grain boundaries are filled with transition metal cations being Mn-depleted and Co-enriched; this makes them virtually not permeable for the Li+ cations, and therefore they negatively influence the Li diffusion in and out of the spherical agglomerates. These results demonstrate that besides the mechanisms intrinsic to the crystal and electronic structure of Li-rich cathodes, their rate capability might also be depreciated by peculiar microstructural aspects. Dedicated engineering of grain boundaries opens a way for improving inherently sluggish kinetics of these materials. | ||||
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| Language | Wos | 000678382900042 | Publication Date | 2021-07-02 | |
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| ISSN | 2574-0962 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | Times cited | 4 | Open Access | OpenAccess | |
| Notes | We thank Dr. M. V. Berekchiian (MSU) for assisting in ICPMS measurements. We acknowledge Russian Science Foundation (Grant 20-43-01012) and Research Foundation Flanders (FWO Vlaanderen, Project No. G0F1320N) for financial support. | Approved | Most recent IF: NA | ||
| Call Number | UA @ admin @ c:irua:180556 | Serial | 6841 | ||
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| Author | Samal, D.; Gauquelin, N.; Takamura, Y.; Lobato, I.; Arenholz, E.; Van Aert, S.; Huijben, M.; Zhong, Z.; Verbeeck, J.; Van Tendeloo, G.; Koster, G. | ||||
| Title | Unusual structural rearrangement and superconductivity in infinite layer cuprate superlattices | Type | A1 Journal article | ||
| Year | 2023 | Publication | Physical review materials | Abbreviated Journal | |
| Volume | 7 | Issue | 5 | Pages | 054803 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
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| Language | Wos | 001041792100007 | Publication Date | 2023-05-30 | |
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| ISSN | 2475-9953 | ISBN | Additional Links | UA library record; WoS full record | |
| Impact Factor | 3.4 | Times cited | Open Access | OpenAccess | |
| Notes | Air Force Office of Scientific Research; European Office of Aerospace Research and Development, FA8655-10-1-3077 ; Office of Science, DE-AC02-05CH11231 ; National Science Foundation, DMR-1745450 ; Seventh Framework Programme, 278510 ; Bijzonder Onderzoeksfonds UGent; | Approved | Most recent IF: 3.4; 2023 IF: NA | ||
| Call Number | EMAT @ emat @c:irua:196973 | Serial | 8790 | ||
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